Generating Survey Data Files (DAT)

You also have the option converting elevation data into a standard COMPASS survey data file (DAT). As a survey data file, the elevation model can be compiled and linked to multiple caves. It is thus more flexible than directly linking the data to a plot file.

Exporting A Dat File. To export the elevation data as a survey data file, select "Link" or "Edit" buttons from the tool bar. This will bring up the "Cave To Surface Linker" window. Select the second page and then click on the "Save As Survey" button and choose a file to in which to save the data.

Using The File. The exported survey data file will contain a set of shots that form a mesh of the surface elevations. You do not have the option of generating contours. Each station in this pseudo-survey is one of the elevation points. Since the COMPASS editor will only handle 1500 shots at a time, the file may be too large to edit if you have lots of elevation points. This not a problem since, in most cases, you won't have any need to edit the file. If you do need to edit, you can use an ordinary text editor such XED, which is available at https://www.fountainware.com.

Linking To Caves. Each station in the pseudo-survey is labeled with the row and column of the grid of elevation points. For example, the point at column four and row six will be labeled with "C4R6". To connect a cave to the mesh, all you need to do is connect the cave entrance to a point in the grid. You can do this by substituting the entrance station name with one of the elevation point names. In the example above, if the entrance name were CSU1, you would change it to C4R6. If the entrance is not precisely on one of the elevation points or you don't want to change the entrance station name, you can generate a pseudo-shot connecting the entrance with the grid point.

Locating The Link Point. When you generate a survey data file from the elevation points, you have to locate the connection point for the caves manually. The easiest way to do this is to compile the elevation data file separately, and then view it in the COMPASS Viewer. Using the color-by-depth option and other features of the Viewer, you should be able locate any point on the terrain surface. You then locate the nearest station to the entrance and then link the cave data.

Compiling. Processing a surface file will be slow. This is because each square in the grid is seen as a loop. For this same reason, you should try to close surface data. Finally, since there are no individual surveys inside a surface file, there may be times when it appears that nothing is happening during the compile process.